Similar discussion from previous HN thread:
>Potential Business Applications:
>Sock puppeteering to overthrow a despotic regime
>Brand monitoring and sentiment analysis
>Shilling cryptocurrency at a moments notice for financial gain
>Influencing sentiment on topical issues
>Getting in on price action early
>Running analysis of a telegram channel
While some of them are arguably unethical, some of them are almost certainly not.
Do a search for "site:telegram.me" including a keyword from any illegal activity, such as carding, and you'll find hundreds of channels with interesting behavior.
I don't see any negative ethical aspect to be honest.
It's all relative.
Former head of the National Security Agency Gen. Michael Hayden